Remove stable-8.4 and bad dependency (on Debian)
Remove stable-8.4 and bad dependency (on Debian)

ybertot/opam-coq-archive,gmalecha/opam-coq-archive,gmalecha/opam-coq-archive,mattam82/coq-opam-archive,gmalecha/opam-coq-archive,coq/opam-coq-archive,mattam82/coq-opam-archive,ybertot/opam-coq-archive,ybertot/opam-coq-archive,mattam82/coq-opam-archive